Steam generators



Dec. 5, 1967 K. T. DISLEY 3,356,078

5 TEAM GENERATORS Filed April 4, 1966 O 0o 00 L/ 7777 A tt orney United States Patent 3,356,078 STEAM GENERATORS Kenneth Thomas Disley, Addington, England, assignor to Foster Wheeler Corporation, Livingston, N.J., a corporation of New York Filed Apr. 4, 1966, Ser. No. 552,357 5 Claims. (Cl. 122-480) ABSTRACT OF THE DISCLOSURE A vapor generator for marine use including a division Wall to form an inner radiant chamber and a convection chamber. A primary superheater is located within the in ner radiant chamber. The outer convection chamber includes two compartments, one of which has a reheater therein shielded by a secondary superheater.

It should be understood that the terms water and steam where used herein and in the claims are to be read generically to include any liquid and its vapor unless the context requires otherwise.

In marine boilers, reheaters are generally installed only in the ahead turbine drive and not in the astern drive. When running astern or maneuvering no steam passes through the reheater and, unless special precautions are taken, the reheater may be overheated and seriously damaged. A particulary diflicult situation arises where emergency astern running is necessary since then the boiler has to work at high power. A solution is to install the reheater outside the boiler in an independently fired furnace but that is a complication which it is desirable to avoid.

In accordance with the invention, the boiler is provided with a primary superheater shielded from radiant heat and with a secondary superheater and a reheater which are arranged in that order in the normal gas path from the steam generating section and with means for causing the gases to bypass the secondary superheater and the reheater when desired. The bypass means may be adjustable so that the secondary superheater and the reheater are bypassed by any desired proportion of the gases leaving the steam generating section. Normally after passing over or bypassing the secondary superheater and reheater the gases will pass to an economizer or other heat recovery system.

The primary superheater may be shielded by being positioned in the steam generating section.

An example of a boiler in accordance with the invention is shown diagrammatically in the accompanying drawing, in which:

FIGURE 1 is a sectional elevation of the boiler; and

FIGURE 2 is a sectional plan.

The boiler shown therein is a D-type marine boiler having a steam drum and a water drum 12 connected by a bank of steam generating tubes 14 within which there is arranged a superheater 16 shielded by the said tubes from the fierce radiant heat of the furnace 18. An economizer 20 is arranged in the flue 22 for the waste gases.

The lower part of the flue has two parallel passages 24 and 25 (FIGURE 2). In the passage or reheater compartment 24, there are arranged a secondary superheater 26 connected in series with the primary superheater 16 and a reheater 28 receiving steam which has done useful work. These two appliances are well shielded from radiant heat by a wall 30 which stops short of the floor of the boiler. Dampers 36 are provided at the top of the passage 24.

In the passage or heat absorbing compartment 25, there is arranged a bank of steam generating tubes 29. Dampers similar to the dampers 36 (not shown) are provided at the top of the passage 25. Normally these dampers and the dampers 36 will work in opposite, as one opens or opens partially the other closes or closes partially.

By appropriate adjustment of the dampers 36, the secondary superheater and the reheater can be totally or partially bypassed by the gases passing to the flue.

'Under normal operating conditions, i.e. steaming ahead, the gas path is from the furnace to the flue through the two passages 24 and 25 and by adjustment of the dampers the relative flow through the two passages can be 26. It therefore operates under very favorable conditions.

Under steaming astern or maneuvering conditions, the reheater is not required and although it is in a relatively low temperature zone is still liable to being overheated, particularly in an emergency when the boiler may be required to work at its limit. By adjustment of the dampers 36, however, the gas path can be altered so that no gas or substantially no gas flows over the secondary superheater or the reheater, the full weight or substantially the full Weight of gas passing over the steam generating bank in the passage 25. The full weight of steam, however, passes through the secondary superheater and prevents the latter being overheated which, in turn, provide a relatively cool screen in front of the reheater which is thus protected against overheating.

The economizer 20 can be replaced or supplemented by an air heater or by steam generating tubes.

For controlling the temperature of the steam and safeguarding the secondary superheater and the reheater, steam can be drawn off in any desired amount from the primary superheater and be returned thereto after passing through an attemperator coil 38 arranged in either the steam drum 10 (as shown) or in the water drum of the boiler.

The dampers 36 could, of course, be arranged at the bottom of the passages 24 and 25.

The merit of the invention is that of producing a simple and compact installation which is of paramount importance in a marine boiler. 1

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that details of construction and the 1. A vapor generator comprising:

a setting having a furnace chamber therein, said furnace chamber having a floor;

means for firing said furnace chamber thereby producing combustion gases;

a division wall vertically located and having a lower end above the floor of said furnace chamber to form an opening to permit the flow of combustion gases under the division wall, said division wall separating said furnace chamber into an inner radiant chamher with said means for firing and an outer convection chamber;

a primary superheater located in said inner radiant chamber;

a bypass wall within said convection chamber and located at substantially right angles with said partition Wall and also extending vertically upwardly, said bypass wall separating a portion of said convection chamber into a heat absorbing compartment and a reheat compartment;

a secondary superheater located in said reheater compartment;

a reheater located in said reheater compartment above said secondary superheater;

heat absorbing means located in said heat absorbing compartment; and

means for controlling the relative flow of gases between said reheater compartment and said heat absorbing compartment.

2. A vapor generator according to claim it wherein said heat absorbing means is a bank of vapor generating tubes.

3. A vapor generator according to claim 2 wherein said means for controlling the relative flow of gases between said reheater compartment and said generating compartment is a plurality of dampers at the upper end of. said reheater compartment and at the upper end of said heat absorbing compartment.

4. A vapor generator comprising:

a setting having a furnace chamber therein;

means for firing said furnace chamber thereby producing combustion gases;

a division wall vertically located and having a lower end above the floor. of said furnace chamber to form an opening to permit the flow of combustion gases under the division wall, said division wall separating saidfurnace chamber into an inner radiant chamher with said means for firing and an outer convection chamber;

a primary superheater chamber;

a bypass wall within said convection chamber and lolocated at substantially right angles with said partition wall and also extending vertically upwardly from said primary superheater, said bypass wail separating a portion of. said convection chamber into aheat absorbing compartment and a reheat compartment;

a secondary superheater located in said reheater compartment;

a reheater located in said reheater compartment above said secondary superheater;

a bank of vapor generating tubes, located in said heat absorbing compartment;

a plurality of dampers at the upper end of said reheater compartment and at the upper end of said heat absorbing compartment for controlling the relative flow of gases between said reheater compartment and said heat absorbing compartment; and

located in said inner radiant an economizer within said convection chamber above said plurality of dampers and above saidbypasswall,

5. A vapor generator comprising:

a setting having a furnace chamber therein;

means for firing said furnace chamber thereby producing combustion gases;

a division wall vertically located and having a lower end above the floor of said furnace chamber to form an opening to permit the flow of'combustion gases under the division wall, said division wall separating said furnace chamberinto an inner radiant chamber with said means for firing and an outer convection chamber;

a bank of vapor generating tubes located in said inner radiant chamber;

a primary superheater located in said inner radiant chamber and shielded by said blank of vapor generating tubes located in said inner radiant chamber;

a bypass wall within said convection chamber and located at substantially right angles with said partition wall and also extending vertically upwardly from said primary superheater, said bypass wall separating a portion of said convection chamber into a heat absorbing compartment and a reheat compartment;

a secondary superheater located in said reheater compartment;

a reheater located in said reheater compartment above said secondary superheater;

a bank of vapor generating tubes absorbing compartment;

a plurality of dampers at the upper end of said reheater compartment at the upper end of said heat absorbing compartment for controlling the relative flow of gases between said reheater compartment and said heat absorbing compartment; and

an economizer within said convection chamber above said plurality of dampers and above said bypass wall.

located in said that References Cited UNITED STATES PATENTS 2,092,299 9/1937 Black et al 122-480 X 2,628,598 2/1953 Van Brunt 122-480 2,776,647 1/1957 Hawley l22480 FOREIGN PATENTS 539,615 9/1941 Great Britain.

KENNETH W. SPRAGUE, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,356,078 December 5, 1967 Kenneth Thomas Disley It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 29, for "particulary" read particularly column 2, line 3, for "opposite" read opposition line 27, for "provide" read provides column 4, line 17, for "blank" read bank line 29, for "that" read heat line 32, after "compartment" insert and Signed and sealed this 22nd day of April 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A VAPOR GENERATOR COMPRISING: A SETTING HAVING A FURNACE CHAMBER THEREIN, SAID FURNACE CHAMBER HAVING A FLOOR; MEANS FOR FIRING SAID FURNACE CHAMBER THEREBY PRODUCING COMBUSTION GASES; A DIVISION WALL VERTICALLY LOCATED AND HAVING A LOWER END ABOVE THE FLOOR OF SID FURNACE CHAMBER TO FORM AN OPENING TO PERMIT THE FLOW OF COMBUSTION GASES UNDER THE DIVISION WALL, SAID DIVISION WALL SEPARATING SAID FURNACE CHAMBER INTO ANINNER RADIANT CHAMBER WITH SAID MEANS FOR FIRING AND AN OUTER CONVECTION CHAMBER; A PRIMARY SUPERHEATER LOCATED IN SAID INNER RADIANT CHAMBER; A BYPASS WALL WITHIN SAID CONVECTION CHAMBER AND LOCATED AT SUBSTANTIALLY RIGHT ANGLES WITH SAID PARTITION WALL AND ALSO EXTENDING VERTICALLY UPWARDLY, SAID BYPASS WALL SEPARATING A PORTION OF SAID CONVECTION CHAMBER INTO A HEAT ABSORBING COMPARTMENT AND A REHEAT COMPARTMENT; A SECONDARY SUPERHEATER LOCATED IN SAID REHEATER COMPARTMENT; A REHEATER LOCATED IN SAID REHEATER COMPARTMENT ABOVE SAID SECONDARY SUPERHEATER; HEAT ABSORBING MEANS LOATED IN SAID HEAT ABSORBING COMPARTMENT; AND MEANS FOR CONTROLLING THE RELATIVE FLOW OF GASES BETWEEN SAID REHEATER COMPARTMENT AND SAID HEAT ABSORBING COMPARTMENT. 